The present invention relates generally to a method and apparatus for electrospark alloying (ESA). More particularly, in one embodiment of the present invention, the electrospark alloying defines a micro-welding process for depositing a portion of the rotating electrode onto the work piece to form a fully dense metallurgical bond therebetween. Although the invention was developed for the repair of metallic gas turbine engine components, certain applications may be outside of this field.
Electrospark alloying refers to a micro-welding process that uses a short duration electrical pulse to melt and deposit a portion of a consumable metallic electrode onto a metallic base material. The deposited material alloys with the base material to form a metallurgical bond. The short duration of the electrical pulse allows for the extremely rapid solidification of the deposited material and results in a fine-grained homogeneous weld deposit.
In an electrospark alloying process, the electrode and the work piece are conductive and form the terminal points of a direct current power source. When a surge of energy is applied to the electrode, a spark is generated between the electrode and the work piece. A portion of the metal electrode is melted due to the high temperature of the spark, which is then transferred from the electrode to the substrate surface by short circuit transfer.
The phenomena of transferring a metallic electrode material a base metal by short duration electric arcs has been carried out in a variety of ways over the years. The following references are believed to be representative of such earlier manufacturing processes.
Even with a variety of earlier processes, there remains a need for an electrospark alloying process and an apparatus for electrospark alloying. The present invention satisfies this need in a novel and unobvious way.
One form of the present invention contemplates a welding apparatus, comprising: a main body member; a collet coupled to the main body member and adapted for receiving and holding a consumable electrode; and a heat sink adjacent the collet for cooling the electrode received in the collet.
Another form of the present invention contemplates a an electrospark alloying apparatus, comprising: a supply of inert gas; a main body member; a chuck coupled to the main body member and adapted for receiving and holding a consumable electrode, a portion of the electrode extending from the main body member; a drive coupled to the chuck for rotating the chuck; and a discharge opening in the main body member, the discharge opening is in fluid communication with the supply of inert gas, wherein the discharge opening facilitates a lamellar gas flow adapted for shielding the portion of the electrode.
Yet another form of the present invention contemplates a method for welding high Gamma prime type materials without preheating the base material.
One aspect of the present invention contemplates a process for depositing thick weld deposits with an electrospark alloying system.
One object of the present invention is to provide a unique method and apparatus for electrospark alloying.
Related objects and advantages of the present invention will be apparent from the following description.